Having survived a childhood full of very real monsters, assassin Case Jacobson is now a master at her profession—a killer in the employment of one of the mob's most powerful figures. Existing from day to day, with neither home nor family, Case's life is her job. She completes her assignments with deadly professionalism—never allowing emotions to get in the way... But that is about to change.Rebecca Raines has been working for the mob for three years, slowly making her way up the ranks. Known as Rain to her mobster bosses, the FBI agent has been taking her time in building the case she hopes will eventually bring down the whole Carlotti empire. All the while she's had to do things that have tested her heart and soul, but her latest promotion will be the toughest one of all.Ordered to train Rain as an assassin, Case attempts to do so with her usual detachment, but as Rain slowly chips away at the walls her new teacher has erected around her heart, Case finds herself dealing with emotions long buried. Drawn together as if by destiny, the two are soon fully submerged in a relationship deeper and more passionate than either has ever known. It's a relationship that will challenge everything they know about themselves and the world they live in—indeed that will endanger their very lives, as they soon find themselves spiraling toward an inevitable confrontation both with the Mafia and the federal government.To survive and try to protect the one person who's made her feel again, Case must put into practice her considerable skills as a master assassin, but can Rain overlook her duties as a federal agent, knowing that if she does so, she may be turning her back on everything she believes—but if she doesn't, she could very well be signing a death warrant for a young woman who's come to mean everything to her.